1. Field of the Invention
The present invention relates to a system which realizes the application of a fuzzy theory in terms of hardware.
2. Description of Related Art
In recent years, the application of a fuzzy theory, which is able to treat equivocal knowledge or information by quantifying the same, has been realized in the fields of home electric appliances and plant control. The practical application of the fuzzy theory includes both hardware application and software application and, recently, there has been introduced hardware for exclusive fuzzy use due to demand for increased speed or the like. The exclusive hardware includes analog and digital types of hardware. The present invention relates to the fuzzy hardware of an analog type.
To execute a fuzzy inference, at least, there are necessary a part (a membership function generation circuit) which calculates the goodness of fit between an input value and the membership function of an antecedent part, a part (a minimum value operation circuit) which finds an inference result for every rule, a part (a maximum value operation circuit) which integrates a plurality of inference results, and a part (a non-fuzzing circuit) which non-fuzzes the inference result. If these parts are arranged as a system, then the system is able to execute inference.
In the hardware of an analog type, the value of the membership function is expressed in terms of an analog voltage and a concrete membership function generation circuit is composed of a differential amplifier circuit, an operational amplifier circuit, or the like. Such membership function generation circuit outputs one membership function value for each externally applied input value.
On the other hand, since the shape of the membership function differs according to the object thereof, it is necessary to adjust the membership function shape and, in such shape adjustment, it is convenient to be able to observe the shape of the whole of the membership function. Thus, conventionally, in order to observe the shape of the whole of the membership function set at a glance, a sweep signal generated by a function generator provided externally is input to a membership function generation circuit and the output of the membership function generation circuit is observed on a time axis by means of an oscilloscope or the like. An example of conventional observation of the shape of the membership function is shown in FIG. 6 in which a function generator 100, membership function generator 210 in a fuzzy inference device, and an oscilloscope 300 are connected.
However, in the above-mentioned conventional method, it is necessary to prepare the function generator for generating the sweep signal in addition to a fuzzy inference unit.